1. Field of the Invention
The present invention relates to harvesting reels and in particular to a reel having a segmented cam for orienting the pickup fingers of the reel and for providing a cam path that provides greater engagement of the fingers with the crop.
2. Description of the Prior Art
It is known, as shown in U.S. Pat. No. 4,008,558, to provide a pick up reel for a harvester where the fingers maintain a constant attitude relative to the ground. The path of the fingertips generates a cylinder. A plurality of transversely spaced spiders is attached to the reel shaft having arms that carry rockshafts at their outer ends. The rockshafts are coupled via crank arms to eccentric spiders at the ends of the reel. Fingers depend from each rockshaft and the rockshafts are rotated relative to the spider arms during rotation of the reel so that the fingers maintain a constant attitude relative to the ground.
A similar mechanism is shown in U.S. Pat. No. 5,768,870. There, the linkage mechanism that controls the orientation of the fingers provides a fingertip path that is non-cylindrical. The orientation, or attitude, of the fingers relative to the ground, however, remains constant through the crop engagement region.
Both of the above patents control the finger orientation by a disk that is eccentric to the reel pivot axis. Links extend radially outward from the disk and are coupled to the crank arms that are fixed to the rockshafts. With such a mechanism, the fingertip path is fixed and cannot be adjusted by the user. Some harvesting reels, such as that shown in U.S. Pat. No. 4,008,558, do provide a mechanism by which the attitude of the fingers can be adjusted by the user to provide greater or lesser degrees of lift to the crop. While the attitude of the fingers relative to the ground can be adjusted, the fingertip path is always cylindrical.
Other finger orientation control mechanisms are shown in U.S. Pat. Nos. 5,007,235, 5,566,536 and 5,595,093. These patents all show cams to control the finger attitude. The cams can be circular or irregular in shape to produce varied finger paths and attitudes. One drawback in the prior art is the inability to change the finger path or attitude for changing conditions.